Parents of three- and four-year-olds are eligible for up to 30 hours’ free childcare.
Photograph: Dominic Lipinski/PA

The exclusion of fostered children from the additional 15 hours of free childcare a week available to parents in England is discriminatory and inexplicable, charities have said.

The government’s flagship childcare policy, which takes the potential number of free hours for parents of three- and four-year-olds up to 30 in total, was introduced in September but contained a specific exclusion “if the child is your foster child”.

Thirteen charities, including Action for Children, Become, the British Association of Social Workers,and the Care Leavers’ Association, have denounced the prohibition and are demanding that it be removed.

In a letter to the Guardian, they write: “Children aged three and four across England are now entitled to an extra 15 hours of free childcare each week, with the exception of fostered children who have been explicitly and inexplicably excluded. We are calling on the children’s minister, Robert Goodwill, to urge him to reverse this discriminatory decision with immediate effect. Fostered children must have access to the same opportunities as other children.”

The charities say grandparents and others who foster members of their own family would particularly benefit from access to the additional 15 hours a week, as would long-term carers.

The signatories, which also include Children England, Coram BAAF, and the National Association of Independent Reviewing Officers, stress that foster carers, who are often struggling to make ends meet, should be given as much help as possible.

A survey published by the Fostering Network last month found that the majority of foster carers in England are unpaid or underpaid, with only one in 10 receiving the equivalent of the national living wage for a 40-hour week. Additionally, childcare costs charged by nurseries have risen steeply in recent years.

Daniel Sinclair, communications manager at the Fostering Network, which also signed the letter, said: “Not all foster parents will take up the 15 hours but it ought to be left to their judgment and that of the social worker. Some fostered children thrive when surrounded by their peers.

“This government and the previous government have encouraged people to foster by saying you can combine fostering with working outside the home but [the foster parents] will have to pay for [the additional 15 hours] or enter into difficult negotiations with the fostering service – there’s no obligation for the fostering service to pay for that.”

To claim 30 hours of childcare, both parents must be in work and earning at least the national living wage or, for those under 25, the national minimum wage for 16 hours a week.

When the inclusion or otherwise of foster carers was discussed in the House of Lords in July 2015, the schools minister John Nash said: “Whether foster care is considered work under the eligibility criteria for this additional childcare support is … complicated.”

Lord Nash was responding to representations by the crossbench peer Francis Hare, who said research showed that many of the young children going into care had mental health issues that had not been flagged up. So, he said, it was important they got “the opportunity of being in a high-quality early years setting, where those missed mental health issues may be identified”.

Hare said it was crucial for foster carers “to have all the possible incentives to continue in what they do”.

The policy has been criticised for targeting working parents, who can earn up to £100,000 each and still be eligible, rather than prioritising access for the most deprived families who may not qualify.

The other organisations that signed the letter to the Guardian were Coram Voice, the National Youth Advocacy Service, Tact, the Together Trust, and St Christopher’s.